Jailbreak Detector (X04)

A lightweight Swift extension for UIDevice that checks for common jailbreak indicators.

Status

Legacy reference. Modern iOS integrity checks rely on App Attest (and DeviceCheck), so this heuristic approach is far less relevant today.

Features

• URL scheme checks, file presence scans, and a write test.
• Configurable jailbreak scheme via X0R_KEY in your Info.plist/XCConfig.
• Simple UIDevice API: x04 (jailbroken) and x102 (simulator).

Installation

Use Swift Package Manager (Xcode: File → Add Packages...) with:

https://github.com/deya-eldeen/JailbreakDetector.git

Or add Sources/X04Checker/X04.swift to your project.

Usage

if UIDevice.current.x04 {
    // Device appears jailbroken—take action (disable features, alert user, etc.)
}

SwiftUI sample:

import SwiftUI
import X04Checker

struct ContentView: View {
    @State private var monkey = false
    @State private var showAlert = false

    var body: some View {
        VStack(spacing: 20) {
            Text("Monkey status:")
                .font(.headline)

            Text(monkey ? "🐒 Monkey!" : "✅ Clean")
                .font(.title)
                .foregroundColor(monkey ? .red : .green)
        }
        .padding()
        .onAppear {
            monkey = UIDevice.current.x04
            showAlert = monkey
        }
        .alert("Warning", isPresented: $showAlert) {
            Button("OK", role: .cancel) { }
        } message: {
            Text("Your device appears to have a monkey. Certain features may be disabled.")
        }
    }
}

Example App

A sample iOS app lives at Example/ExampleApp.xcodeproj and uses the package directly.

Screenshots

Clean	Affected

How It Works

JailbreakDetector runs three checks:

1. URL scheme: UIApplication.shared.canOpenURL(URL(string: "<scheme>://")).
2. File checks: scans a list of suspicious paths.
3. Write test: attempts to write outside the sandbox (e.g. /private/monkey_write_test).

Simulator always returns false for x04 to avoid development false positives.

Customization

• Add paths in JailbreakDetector.suspiciousPaths (Sources/X04Checker/X04.swift).
• Change the default scheme ("cydia") or inject X0R_KEY via XCConfig.
• Add logging/metrics around each check if needed.

Build

This package targets iOS and uses UIKit, so build it with Xcode or xcodebuild for an iOS destination.

Xcode:

• Open Package.swift
• Select an iOS Simulator destination
• Build (⌘B)

CLI:

xcodebuild -scheme X04Checker -destination 'platform=iOS Simulator,name=iPhone 14' -sdk iphonesimulator build

Tests

Run tests on an iOS Simulator (UIKit is not available on macOS targets).

Xcode:

• Open Package.swift
• Select an iOS Simulator destination
• Test (⌘U)

CLI:

xcodebuild -scheme X04Checker -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.6' -sdk iphonesimulator test

Optional Obfuscation

Generate an obfuscated copy while keeping a readable source for maintenance:

python3 scripts/obfuscate.py Sources/X04Checker/X04.swift --out dist/X04.swift

Notes:

• Public/open identifiers are preserved automatically.
• Add extra preserved identifiers with --preserve name1,name2.
• This is a best-effort token replacer and does not change string contents or comments (interpolation expressions are updated).
• Replace the Swift file you embed in your app with the obfuscated output.

Credits

• Original concept by Vineet Choudhary.
• Article: Best Way to Check if Your iOS App Is Running on a Jailbroken Phone

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Security disclaimer: No jailbreak detection is foolproof. Always combine detection with server-side safeguards and integrity checks.